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Chapter 7 Reflection Of Light | Exercise 7C

Question 45

A point light source is kept in front of a convex mirror at a distance of 40cm. The focal length of the mirror is 40cm. Find the position of the image.

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"hello students welcome to lido q a video session i am sev your science tutor and question for today is a point light source is kept in front of convex mirror at the distance of 40 centimeter the focal length of the mirror is 40 centimeter find the position of the image to find the position of the image we have to use the mirror formula you can see the gray diagram is given for the reference but the mirror formula over here is mirror formula that is 1 upon v plus 1 upon u is equal to 1 upon f or you can substitute the values let us find v u and f which is given in the question so first of all we need to find the position of the image position of the image will be at will be v v is the position of image u u is the object distance distance of object from the mirror you can see the object is placed in front of the mirror and it is 40 centimeter from the mirror so in front and 40 centimeter that means minus 40 centimeter f the focal length the focal length of the mirror is 40 centimeter so f is equal to 40 centimeter now if you look over here then you have to apply the mirror formula we need to find v so 1 upon v is equal to 1 upon f minus 1 upon u 1 upon 40 minus 1 upon minus 40 1 upon 40 plus 1 upon 40 that is 2 upon 40 and that is 1 upon v hence v is equal to 40 by 2 so value of v comes out to be v is equal to 20 20 centimeter hence we can say that the position of image is 20 centimeter and it is clear that it is positive so it will be on the right side of this mirror which is shown here in the ray diagram you can see 20 centimeter is here this is the image 20 centimeter at the back side of the mirror so we can write here it that position of image is 20 centimeter behind the mirror if you have any queries you can drop it in comment section and subscribe to lido for more q a thank you for watching"

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Question 45

A point light source is kept in front of a convex mirror at a distance of 40cm. The focal length of the mirror is 40cm. Find the position of the image.

  • Solution

  • Transcript

"hello students welcome to lido q a video session i am sev your science tutor and question for today is a point light source is kept in front of convex mirror at the distance of 40 centimeter the focal length of the mirror is 40 centimeter find the position of the image to find the position of the image we have to use the mirror formula you can see the gray diagram is given for the reference but the mirror formula over here is mirror formula that is 1 upon v plus 1 upon u is equal to 1 upon f or you can substitute the values let us find v u and f which is given in the question so first of all we need to find the position of the image position of the image will be at will be v v is the position of image u u is the object distance distance of object from the mirror you can see the object is placed in front of the mirror and it is 40 centimeter from the mirror so in front and 40 centimeter that means minus 40 centimeter f the focal length the focal length of the mirror is 40 centimeter so f is equal to 40 centimeter now if you look over here then you have to apply the mirror formula we need to find v so 1 upon v is equal to 1 upon f minus 1 upon u 1 upon 40 minus 1 upon minus 40 1 upon 40 plus 1 upon 40 that is 2 upon 40 and that is 1 upon v hence v is equal to 40 by 2 so value of v comes out to be v is equal to 20 20 centimeter hence we can say that the position of image is 20 centimeter and it is clear that it is positive so it will be on the right side of this mirror which is shown here in the ray diagram you can see 20 centimeter is here this is the image 20 centimeter at the back side of the mirror so we can write here it that position of image is 20 centimeter behind the mirror if you have any queries you can drop it in comment section and subscribe to lido for more q a thank you for watching"

Our top 5% students will be awarded a special scholarship to Lido.

subject-cta
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